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No, it's not a new concept (someone above mentioned their car having it in 2004, but I know for a fact that some Japanese auto manufacturer had a dead-reckoning nav system even back in the 1980's or 1990's), and it's not new for U-Blox either (I worked at a defense contractor, and we used U-Blox GPS receivers, I personally worked with them, and knew of their dead-reckoning technology, and this was almost 10 years ago now), but U-Blox makes GPS receivers for high-end embedded applications, not so much for co

cutting-edge GPS receivers can pull satellite signals out from all the way down to a few dB above the noise floor now, even in "urban canyon" locations where signal is blocked by buildings as well as being muddled.

I'd certainly hope so, considering that the satellite signal is considerably below the noise floor once it reaches the ground... (sources vary between 20dB [ucalgary.ca] to 26dB [gpssource.com] below the noise, I didn't do the math myself)

Yup, my Peugeot (that's a European car maker) has that. Works superbly. Still knows where you're going when you're 3 floors down in an underground parking. Gives very funny results when you take a ferry which turns 180 degrees before docking.

In fact the very first in car navigation systems used dead reckoning. Honda made one with a map on a cylinder and a little cross hair that you positioned over your starting position. As the car moved the cylinder rotated and the cross hair moved from side to side, following your position on the map.

Android phones have had the ability to use dead reckoning for years now too.

Android phones have had the ability to use dead reckoning for years now too.

Citation needed. This sounds like bullshit. You get dead reckoning by connecting to some sort of feedback device, namely the wheel sensors or odometer in the vehicle. Android phones don't have a connection to your car's computer; they work entirely off of GPS signals. In-car nav systems aren't like this; they use both GPS and dead-reckoning to get better accuracy than GPS alone (watch what happens when you drive into a parking g

You get dead reckoning by connecting to some sort of feedback device, namely the wheel sensors or odometer in the vehicle. Android phones don't have a connection to your car's computer; they work entirely off of GPS signals.

In theory, if the accellerometers and gyroscopes were precise enough, they could use those. Airplanes were already using inertial reference systems way before GPS was invented. Initialise the box with a starting position while standing still, and it will keep track of where you are using just gyroscopes and accellerometers. Taking the rotation of the earth into account and all.

Unfortunately, though, accellerometers in even today's newest phones are nowhere near precise enough for that purpose.

So how do you filter out all the extra accelerations from the users dropping the phone on the floor, fiddling with it, moving it around, etc. while the car is in motion? Phones aren't rigidly mounted in cars.

And considering how often Google Maps thinks I've instantly teleported to different places while driving, it doesn't look like all this theory really holds up in reality.

Those accelerations aren't 'extra' - they are really happening to the phone and so would have to be taken into account too.

The problem isn't that the phone is moved around in the car, the problem is that the accelerometers and gyros of the class that exist in phones are orders of magnitude too noisy and imprecise to be used to dead-reackon for more than a few hundred milliseconds.

There is absolutely no way on earth that any cellphone that exists today uses any of its inertial sensors as part of its GPS solu

So how do you filter out all the extra accelerations from the users dropping the phone on the floor, fiddling with it, moving it around, etc. while the car is in motion? Phones aren't rigidly mounted in cars.

They'll either cancel out (if it ends up in the same place) or be within an acceptable margin of error (most GPS units aren't accurate to the distance between the right front and real left seat anyway).

And considering how often Google Maps thinks I've instantly teleported to different places while drivi

There used to be an option called something like "sensor aiding" which used accelerometers to reduce GPS power consumption and provide some coverage when the GPS signal was lost. For example when driving the GPS could drop down from 1 update/second to 1 update/10 seconds and use the accelerometer to check that the vehicle maintains a more or less constant speed in-between. Accelerometers use a lot less power than GPS.

Most phones have accelerometers. They are very cheap and necessary for things like screen r

I sort of doubt Android phones have any useful sort of dead reckoning. My experience of playing around with accelerometers on phones is that they can tell you roughly which way is up and can detect sharp shakes or jolts and that is all. Attempting to integrate the results over any period of more than about a second results in drift so bad it is useless.

2004? I was working on vehicle location systems that had DR at least 10 years before that (especially useful since IIRC there wasn't a full GPS satellite constellation then). DR isn't exactly new - Columbus used it.

Use of accelerometers is only to reduce the error. Unfortunately, accelerometers can be wrong - due to rotation, deceleration, and acceleration when there is no feedback on WHAT is causing the readings

Cars don't fly. As long as you have traction, measuring distance shouldn't be a problem (especially if you supplement wheel axle sensors with an optical device similar to modern computer mice, to compensate for the tire pressure, and integrate the data). Unlike with airplanes and ICBMs, you shouldn't need precise acceleration from the accelerometers, vehicle orientation along the three axes is what you need. Direct distance measurements obviate the need for double integration (but are impossible in subs, ai

You don't even need to go to all that trouble. That kind of accuracy simply isn't necessary in a car as long as it has GPS. Dead-reckoning, in an in-car navigation system, is only needed to make up for the inaccuracy with GPS, which is mainly because you sometimes lose the signals (inside a parking garage, around too many tall buildings, etc.). You don't normally lose GPS signals for a very long amount of time, only short periods. So DR is just a supplement, and the vehicle's odometer signal alone is en

Without good DR you don't have to lose a GPS signal in a large city for a nav system's positioning to utterly fail. An Urban Canyoning effect can render GPS unreliable despite a strong signal. I've seen GPS in a mile long urban canyon position a vehicle in and across a parallel river in the middle of the canyon. The ultimate solution when this behavior is detected is to rely solely on DR, which in practice can go days of driving before being significantly inaccurate.

Surely you can use both, even if your DR data is not so great; just use the DR data to verify the GPS data makes sense. If the GPS signals say the vehicle has suddenly teleported into a river, check that against the DR. If the DR data says you're still driving straight, then disregard the GPS data until it agrees with the DR data.

It seems like the algorithm could be tweaked a little so that if the GPS is showing the car in a river, a forest, a building, etc. instead of driving on a road as DR indicates, then DR should be favored. After all, it simply doesn't make any sense for the vehicle to be in a river. Or, if you're taking an exit ramp, and the GPS signals show the vehicle veering off into the trees while DR just shows the vehicle is proceeding around the curve at a normal rate, then it should be pretty obvious that the vehicl

You don't even need to go to all that trouble. That kind of accuracy simply isn't necessary in a car as long as it has GPS.

If you define "trouble" as the cost of hardware, I'd argue that I've outlined a route that is as trouble-free as possible, since it doesn't require anything fancy (in terms of manufacturing costs - a high-precision inertial platform would be an example of "fancy" in this sense).

That kind of accuracy simply isn't necessary in a car as long as it has GPS.

I was actually looking forward, towards automated cars. But then again, those will have situational awareness requirements so high that deriving the motion data from CV might be a necessary option anyway (at least in urban settings -

I assume that military units (ships, submarines, airplanes) have been integrating navigational data from multiple sources (LORAN, GPS, INS...) for decades. Nothing else would make sense in case a war erupts, really (you can't rely solely on sats when (a symmetric) war happens).

That is absolutely true. The whole idea of navigation, wether it is on land or at sea is that you take measurements. From a practical standpoint it doesnt really matter wether that is from celestial bodies (natural or man-made) or from known landmarks.One of the problems a sumarine (whilst being submerged) has is that it can`t do any measurements of that kind. Like LORAN-C, GPS, INS, landmarks, celestial navigation et cetera. So angle, distance and time are the main navigational tools. The main skewing fact

One of the problems a sumarine (whilst being submerged) has is that it can`t do any measurements of that kind. Like LORAN-C, GPS, INS, landmarks, celestial navigation et cetera. So angle, distance and time are the main navigational tools

It could also make gravimetric measurements. And it absolutely has to use INS. But then again, unless it's an SSBN, even at war, occasionally sticking out the electronic mast to get a GPS fix doesn't seem to be a problem. After all, a fast attack submarine has to communicate from time to time, and it can get a navigational fix whenever it's forced to stick out the mast for reasons of communication. On open sea, an error of a mile a day [vectornav.com] seems to be good enough when traveling underwater for most purposes.

Close, you use the speed sensor to figure out speed and the steering wheel sensor to figure out direction.Cars only have individual wheel sensors for ABS/stability control. No other systems touch those sensors.

I know I can upset my ABS system, bringing on the the error light, by doing burnouts and handbrake slides. Burnouts give false readings on the from wheels and handbrake slides give false reading on the rear wheels.

Would play havoc with such systems but to be fair I don't normally do these while navigating.

Early Sperry-Rand gyros were too large for a phone andperhaps not as good as modern micro machined devicestoday but could get them from A-B-C.... Recall the oldish phraseclose only counts in horseshoes, hand grenades and A-bombs.

In an age where our phones have accelerometers and compasses, it's amazing your car is still trying to catch up, right?

Actually I think it's the opposite, it's only being in a car that makes dead reckoning with any kind of accuracy feasible. A car is a reasonably large and stable platform, which already has good speed information, and can have some accelerometer-type information added relatively easily. A smartphone does have an accelerometer, but the data is far too noisy to do reasonable dead reckoning, because in addition to the macro movements (someone walking, biking, or driving down a street) there area bunch of micro-movements that produce high local acceleration (putting the phone in/out of pockets, taking steps while the phone's in your pocket, etc.). It makes for a much more complex dead-reckoning problem, because instead of just tracking broad movements (car goes 10m this way) you have to resolve a ton of tiny movements (phone was moved 0.3m into pocket, then rapidly accelerated 0.1m left due to owner being jostled on the subway, etc.), which tend to pile too much accelerometer noise on top of the broader movements that you really want to track.

In short, taking a known starting position and keeping it updated via accelerometer data is a lot easier if your accelerometer is on a car, vs. on a handheld device.

Dead reckoning works fine on my phone. Some apps, like Navitime, let you navigate on foot inside stations where there is no GPS signal using it.

All you have to do is average the readings out. You don't need pinpoint accuracy, and GPS typically only gives you +/-5m on a good day anyway. A car will have lots of random juddering too in counties with shit roads like the UK.

It only seems to be supported in the Japanese version, probably because they have better data for train station layouts available.

It's actually quite a clever system. It can tell when you are on the train because of the high rate of acceleration. When get start walking the rate is constant but low. It knows the distances in meters and does a rough estimate using the accelerometer to notify you when you need to change direction.

Not only that, but the car is on a road and the nav system knows where the roads are. If the nav system has an approximation of the location of the car, and the car makes a right turn, then it can know and sync the position of he car to be on that road.

My old cheap Samsung tracks via accel. and compass most of the time, because the GPS is so poor. As long as it can get a GPS fix every few minutes it covers up for the crappy GPS antenna quite well. IIRC the 'Tomtom' that I used to use at work would do the same thing, only of course it didnt need the capability near as often, but you could drive through a long tunnel with it and still show actual position until the signal re-established at the other end.Presumably there is something new here, but the basic

IIRC the 'Tomtom' that I used to use at work would do the same thing, only of course it didnt need the capability near as often, but you could drive through a long tunnel with it and still show actual position until the signal re-established at the other end.

The dedicated sat-navs tend to just assume that you are continuing at the same speed on the same road. Than give up after a period of time.

There was a system called ETAK (1983... see wikipedia). At the time they "Said" Etak was a Polynesian word that meant "the world moves" and that the technique came from the polynesian nevigation methods.

Yup, this, I think. I definitely remember in my much younger years a Popular Science review of a system that used dead reckoning, basically you told it where you were to start, and it used distance measuring, nothing as sophisticated as accelerometers, but whenever you turned a corner it would realign itself to the map.

It did not work well if you drove many miles in a straight line, but worked well in city driving, which of course was all that was needed when people could still use a map to find the right

Beta is more than cosmetics or aesthetics. The new design ruins the one thing that makes/. what it is -- the commenting system. I only come here for the comments [slashdot.org], not the 2-day old articles nor the erroneous summaries.

I do not see the changes of Beta as improvements. What is wrong with Slashdot that demands breaking its foundations? This is not change for the sake of change, but, as others have commented, an attempt to monetize/. at any any cost [slashdot.org], and its users be damned.

seriously, my old bimmer's on-board navigation already did this 15 years ago !
other than that, I've used u-blox in several embedded designs, and they are by far the most fun GPS unit to play with. They have some great pc software for it too. And they've had this functionality for quite some time now.
oh yeah, and boo to beta..

Inertial Navigation is where you have a set of gyro's and accelerometers measuring your movement in 3 dimensions for aircraft and submarines and in two dimensions for land based vehicles, which in turn is used to update your position based upon an initial position fix ( or in this case the last fix from the GPS ).

Dead Reckoning is simply, "I have been going on course 213 for the last three hours at 5 knots so I must be here." The difference is

You raise the topic of gyros, when they are not mentioned in TFS or TFA. So forget that.

Accelerometers simply enable the estimated speed and direction to be kept up to date. And using that to update position is dead reckoning, as we have both described.

Finally the company themselves call the product 3D Automotive Dead Reckoning. So how the fuck can the summary title be wrong? You think you know what their technology is better than the company do themselves?

Accelerometers simply enable the estimated speed and direction to be kept up to date. And using that to update position is dead reckoning, as we have both described.

But that is not DR since those accelerometers can account for set and drift, and by definition that is inertial navigation. DR is simply I am at point X NOW and if I go in a direction for n amount of time at a given speed I will be at point Y. There is no interpositional correction.

As a pilot I frequently fly without a GPS, hence to better understand my position ( other then looking down at the ground and matching features to a chart ) I rely on reports of wind speed and direction at various altitudes to

But that is not DR since those accelerometers can account for set and drift, and by definition that is inertial navigation.

Again, inertial navigation uses gyros. This doesn't.

And since you are quoting from Wiki:"An inertial navigation system (INS) is a navigation aid that uses a computer, motion sensors (accelerometers) and rotation sensors (gyroscopes) to continuously calculate via dead reckoning the position, orientation, and velocity (direction and speed of movement) of a moving object without the need for external references."

If it looses contact with the satellite it is pretty much just plain lost, now throw in a fairly accurate gyro and set of accelerometers and when the satellite signal goes bye bye you flip over to inertial navigation which can be made pretty accurate since given the fact that cars generally stay on known roads you can then perform path inference based upon the on board map so that if the inertial system seems to think you are driving through a building the system can correct itself by looking at where it has been and put you position back on the road where you should be.

Correct in principle, but drift will kill your signal within a few seconds when you rely on the current crop of MEMS for this. Remember, you need to integrate *twice* to get from acceleration to position, and any noise will grow the position error exponentially. If you go with aircraft grade accels, be prepared to spend more than the price of your car for a decent system. This will be precise enough to keep you on track for a few hours, but don't expect this to be part of your next car's nav system anytime

Don't know who well it works, but there was a demo by Apple's iOS developers where they combine GPS and WiFi. In towns with large buildings and awful GPS reception you will usually have tons of WiFi signals around, so at least in principle it should be possible to improve navigation using both.

But as to which did it first, that was iOS. How do I know? Because iOS was using Skyhook Wireless for location in the very first iPhone. And iPhone launched before any Android devices.

The trick is actually to use both GPS _and_ WiFi. In most places, GPS should be a lot more accurate. Except in towns, where you have (a) huge buildings making GPS suffer, but at the same time (b) lots of WiFi signals so you can probably average out the inaccurate data from them. With a bit of maths you could probably use change in signal strength to improve things if you receive multiple WiFi signals.

A few months ago I left work to run some errands and stuck my Android phone in its car charging dock (which automatically activated my preferred nav program). Six or seven miles down the road I noticed the icon representing my car was different than normal and my location was about a half-block off my actual position. At the next stoplight I checked and discovered my GPS was turned off. My phone had reasonably calculated my position through several turns and stops using only the accelerometer (dead-reckonin

Phones have Location Based Services (LBS) on a typical phone also uses wifi, GPS and Cell Tower location. A request to LBS expects should return a reasonable fix to the highest accuracy. In a dense urban environment, there is a lot of information from wifi/Cell to give a good fix - probably better than GPS. They have a magnetometer that is affected by materials around them and is not guaranteed to be aligned in a consistent way to the movement. In a dock,

The automotive nav system I work on has 2D dead reckoning, relying on GPS for altitude. 3D dead reckoning is news to me, and I suspect is the intended newsworthy bit here. When GPS fails and the digital terrain model doesn't account for urban landscapes like parking garages, both above and below ground, and tunnels, positioning is calculated in software. It's an expensive, imperfect process I imagine can at least be offloaded to sensors, if not improved, as possibly done in this chip. That would certainly f

A GPS which receives speed, wheel position and reverse light data from the car does dead reckoning. I watched a friend's car do it just this weekend as we drove into an underground parking garage where you get no GPS reception.

Dead reckoning for car NAVs has been around forever, it actually predates GPS. The first in-car NAV systems by Etak were made using only maps and dead reckoning because GPS didn't exist yet. It also predated affordable LCD panels.

Dead reckoning technology is actually very old. It has been used to guide missiles, submarines, and of course cars for decades even before the GPS was invented. It is the technology used by sailors before they had GPS as well. The idea is simple and complex at the same time: use some specific known reference, guess what's happening in the absence of reference, and recalibrate once a new reference becomes available again . References can be the sun, stars, towns, or GPS itself.

You are correct. Particularly dead reckoning based on stars has been used for centuries for navigating across oceans. I was referring mainly to computer-based dead reckoning, which involves quantifying the error of your estimation based on a mathematical model, and how modern dead reckoning works.

We've all been there. You're relying on your vehicle's built-in navigation system to get to that meeting downtown,

Errr, no.

What is the usage case again?

You're in a concrete canyon downtown. So what the fuck are you doing driving? That's what taxis and tube trains and buses are for. Cars in the city centre are almost always a guarantee for frustration and delay.

Besides, if it's your own city, how on earth can you exist without knowing it at least as well as the Sat Nav, and also knowing the pedestrian-onl

Dead reckoning automotive navigation predates GPS and predates what would have become Geostar. Sure, the hardware is cheaper now, and algorithms might be better, but there's nothing new about this concept. Welcomed? Sure. But don't pretend it's a new idea.

Don't forget nntp://comp.misc [comp.misc] on Usenet(although I doubt there are any modern browsers that support the nntp:// [nntp] protocol* anymore so you will have to join mainly by downloading a free usenet client, sign up to eternal-september.org and adding comp.misc to your subscribed newsgroup list)

Still, if people are willing to use old school IRC then Usenet isn't much worse;-)